Mechanical pencil of screw feed type



Aug. 219, 1950 w. J. PARISH MECHANICAL PENCIL 0F SCREW FEED TYPE Filed July 25, 1947 INVENTOR. WILLIAM J. PARISH ATTORNEYS.

Patented Aug. 29, 1950 UNITED STATES TNT OFFICE 4 Claims.

The present invention relates to pencils having a permanent pencil body with means internally of the body for containing and feeding a supply of socalled lead or other solid writing material as needed, and, more particularly, to such a pencil having novel lead gripping means and novel means for propelling the lead to feed and retract the some. Pencils of the type with which th invention is concerned are usually referred to as automatic or mechanical pencils.

In accordance with the invention, a lead holding means is provided which grips the lead in a positive manner by penetrating beneath its surface as by scoring or cutting. The scoring or cutting oi the lead is preferably in the nature of a threading operation which is conveniently car ried out when loading fresh lead into the pencil. More in detail, the gripping means of the invention is in the form of a device for scoring or cutting a thread in the cylindrical surface of the lead at its end. This device is externally thread-- ed and is rotatable with respect to the internally threaded .body of the pencil .so that it moves longitudinally of the pencil body. Rotation is imparted to the gripping means by novel lead bracing means which is rotatable by an externally exposed rotatable means forming a part of the pencil. This .last named means or part is prefer ably located at the writing end of the pencil.

An important object of the invention is to provide, in a novelmanner, for gripping, bracing and propelling the solid writing material, such as a length of lead, in a mechanical pencil.

Another object is to provide a mechanical phcil having novel means for gripping the lead.

A further, and closely related object, is to provide novel lead gripping means in a mechanical pencil which scores or cuts the lead, thereby to obtain a and durable grip on the lead.

Still another object is to provide a novel lead guiding and bracing means for a mechanical pencil.

A still further object is to provide a novel means for propelling the lead in a mechanical pencil to feed or retract it.

Other and, perhaps, more specific objects of the invention will become apparent or suggest themselves to those skilled in the art as the following description proceeds with constant reference to the accompanying drawing in which:

Fig. 1 is a longitudinal section through the pencil body or barrel of a pencil embodying the invention in one form;

Fig. 2 is an enlarged transverse section taken on line 2--2 of Fig. 1';

Fig. 3 is a section on line 3- 3 of Fig. 2.

Fig. 4 is a longitudinal section of a pencil embodying the invention in a modified form, certain of the parts being shown in exploded relationship for the sake of clarity of illustration; and

Figs. 5., 6 and 7 are enlarged transverse sections taken on lines 55, .65 and .l-l, respectively, of Fi Referring to the illustrative embodiment of the pencil it of this invention, which is shown by Figs. 1, 2 and 3 of the drawings, it is seen to comprise .a cylindrical body or barrel 92 having an internal here It enclosed by the cylindrical wall it. The pencil it is provided With a tapered gripping end 11 in the usual manner to provide a comfortable holding portion for the fingers of the user.

The cylindrical body 12 and the grippin end I] are joined in rotatable relationship by .a sleeve it having .an inwardly projecting flange 2! which is received in a circular groove 22 at or adjacent to the end of the body H. The sleeve 69 may be in the form of a snap ring of springy material, such as brass, stainless steel, or other metal; or a flexible plastic.

An .aXial bore or hole .24 is provided in the tapered gripping .end ll of the pencil it, to provide a lead nozzle and it is approximately the diameter of a stick 2.5 of lead or other writing material which is designed to .be used with a pencil of the type with which the present invention is concerned. It will be understood that the stick 25, hereinafter referred to as the lead, may be of any desired diameter and that manufactured pencils embodying features of this invention may be constructed to suit any desired type or lead. If desired, .a short extended portion 2% may be included to brace the protruding end of the lead .25.

The body i2 may be formed of a plastic .or any suitable metal, such as a precious metal for ornamental purposes. Because 01 the relatively simple nature of the body l2, it may be molded, turned or otherwise formed by well known manufacturing processes. l he external surface of the wall l 6 may be circular as shown or may have any desired configuration and ornamentation.

The wall it, surrounding the bore id, .is provided with a screw thread 2? which may be molded, or out by ordinary screw-cut methods. The thread 27 may be of the multiple type Where, as is usually the case in writing instruments of this kind, a quick-screw action is desired. A spare lead olding chamber 28 in the form of a hollow extension 29 for the body I 2 is preferably provided which has a reduced threaded end 36 to be received by the thread or threads 21. The opposite end 35 of the extension 29 may be formed or fitted to receive a closure member 32. This closure member may be in the form of an eraser (not shown) or a jeweled ornament (not shown). In the illustrative embodiment the closure member is shown as a simple cap or plug, but it may have the features suggested immediately above.

The lead 25 is gripped at its end internally of the pencil by the novel gripping means 34 of this invention which comprises two similar parts 36 and 31. The part 31 is shown in elevation by Fig. 3 of the drawings. The parts 36 and 31 are shown in assembled relationship in Figs. 1 and 2 of the drawings in which they are held by a key 39 in a keyway 38. Each part is provided with external screw threads 48 and 4! which provide a continuous thread (or threads) to engage the thread'Z'l in the body 52 when the parts 33 and 31 are assembled together in the body l2 in lead gripping relationship. The part 36 has a recess or slot 42 and the projections 44 and 46 on each side of this slot have internal threads 48 cut or otherwise formed therein. The part 36 is provided with two recesses 49 and 51 leaving a single projection 53 having internal threads 54 cut or otherwise formed on its end. It will be understood that the threads 48 and the thread 54 are segments of a continuous geometrical thread.

A plurality, three in number in the illustrative embodiment, of rods designated 55, and 5B project into the bore 14 from the tapered griping end i! of the pencil body [2. These rods may be constructed separately of metal or other suitable material and they may be secured in the material of the end I! of the body l2. They may be integral with the end I! as shown in the drawings for the sake of the convenience of illustration. The cross sectional outline of these rods is such as to seat within the slots or recesses 42, 49 and 5| of the parts 36 and 3'! of the gripping means 34.

It is believed that assembly and operation of the pencil I!) of the embodiment of Figs. 1 to 3 will be understood from the foregoing description when taken in connection with the figures of the drawing referred to. For the sake of completeness of description, a brief discussion of the mode of operation and assembly will now be given. To insert the lead 25, the gripping means 34 is preferably in the position shown by Fig. 1 of the drawings. The key 39 is engaged in the keyway 38. The lead is inserted through the nozzle hole 24 and is pushed up to the gripping means 34. It is then screwed into the threads 48 and 54 which are in helical alignment when the parts 36 and 3! are in assembled relationship. When the tapered end !1 is rotated with respect to the body or barrel !'2, the means 34 is revolved by the rods 53, 51 and 58. The means 34 will move longitudinally of the bore l4 in either direction, depending upon the direction of relative rotation to propel or retract the lead 25.

s. 4 to '7 of the drawings show a modification of the pencil l 0 of Figs. 1 to 3. As certain of the parts are similar, and in some instances identical, such parts will be designated by reference characters having the suffix a. The modifled pencil lea is provided with a cylindrical body [2a having an internal thread 21a. The end of the body is provided with an external screw thread 64 which receives an internal thread. 6

of a cap member 68. The lead gripping means 34a is similar to the means 34 of Fig. 1 and comprises parts 36a and 31a. A tapered gripping part Ila has a bore 24a therein which receives the lead 25a. The cylindrical body l2a and the tapered part [1a are joined in rotatable relationship by a sleeve l9a having an inwardly projecting flange Zia which is received in a circular groove 22a at the end of the body l2a. Rods 56a, 57a and 58a are provided which are similar to the rods 56, 57 and 58 of Fig. 1, except that they project somewhat beyond the end of the pencil body l2a. They are received at their ends in a bore '18 in the cap member 68 when the cap member is assembled to the pencil body lZa. The rods are, of course, rotatable in the bore 18 which exercises a bracing function. From the preceding description it is believed that assembly and operation of the modified pencil Illa will be understood.

The invention claimed is:

1. A mechanical pencil comprising a casing having a threaded bore, an axially movable two part a lead holding device therein having a threaded periphery to engage the threads of the bore, said axially movable means having screw cutting means internally thereof to receive and cut threads in an elongated piece of lead, said pencil having a tip rotatable with respect to said casing, and a plurality of rods rotatable with said tip and extending into and through said lead holder thereby to rotate said lead holder to move said lead axially.

2. A mechanical pencil comprising a casing having a threaded bore, an axially movable two part die therein having a. threaded periphery to engage the threads of the bore, said axially movable die having screw cutting means internally thereof to receive and cut threads in an elongated piece of lead, said pencil having a tip rotatable with respect to said casing, and a plurality of rods rotatable with said tip and extending into and through said die thereby to rotate said lead holder to move said lead axially.

3. In a writing instrument, the combination of a casing having a hollow interior, internal screw thread means on the inner wall of said casing, writing material gripping means received by said thread means in threaded engagement, revoluble means accessible externally of said casing for rotating said lead gripping means, a plurality of rods extending from said revoluble means and disposed to be in close and bracing engagement with writing material retained by said lead gripping means, said writing material gripping means having a plurality of recesses therein slidably to receive said rods.

4. The combination of claim 3 wherein said gripping means are provided with threads threadedly to engage a stick of writing material inserted therein.

WILLIAM J. PARISH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 23,487 Pierce Apr. 5, 1859 272,700 Jaeger Feb. 20, 1883 474,972 Sack May 17, 1892 579,596 Mathiesen i Mar. 30, 1897 

